Image management apparatus, management method, and storage medium

ABSTRACT

An image management apparatus generates, from a plurality of metadata respectively corresponding to a plurality of images, summary data of the plurality of metadata, and stores the summary data in association with the plurality of metadata.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image management apparatus and amanagement method.

2. Description of the Related Art

If movies shot by a monitoring camera are continuously recorded in arecording apparatus, the data amount of the movies recorded in therecording apparatus becomes enormous. To efficiently detect and checkabnormal circumstances from the enormous amount of recorded movies, somemonitoring camera systems execute video analysis processing, and performprocessing of assigning predetermined information to a movie. As atechnique of assigning predetermined information to a movie, there areprovided techniques described in, for example, Japanese Patent Laid-OpenNo. 2004-112005 and U.S. Pat. No. 7,460,601.

Japanese Patent Laid-Open No. 2004-112005 describes an image recordingapparatus which records, if a change occurs in continuous image datashot by a camera, the change level and changed portion as indexinformation. To play back the recorded images, the image recordingapparatus described in Japanese Patent Laid-Open No. 2004-112005 refersto the index information, and plays back only the changed portion.According to this technique, it is possible to readily check images shotby a camera.

U.S. Pat. No. 7,460,601 describes a movie monitoring system in which amovie transmission apparatus divides movie data into predeterminedunits, assigns associated metadata to each divided movie data, andtransmits the movie data and metadata to a movie reception apparatus.According to this technique, it is possible to improve the efficiency ofan accumulation process and search process.

In the techniques of the above-described patent literatures, byassigning predetermined information such as metadata to image data ormovie data to be recorded, succeeding detection and checking processesare efficiently executed. In either of the patent literatures, however,the amount of information assigned to image data or movie data of a longtime becomes enormous, and thus the load of a search process cannot besufficiently reduced.

SUMMARY OF THE INVENTION

The present invention reduces the processing load and allows anefficient search when searching assigned metadata to extract desiredimage data.

According to a first aspect, an image management apparatus comprises: ageneration unit configured to generate, from a plurality of metadatarespectively corresponding to a plurality of images, summary data of theplurality of metadata; and a storage unit configured to store thesummary data in association with the plurality of metadata.

According to a second aspect, a management method for an imagemanagement apparatus comprises: generating, from a plurality of metadatarespectively corresponding to a plurality of images, summary data of theplurality of metadata; and storing the summary data in association withthe plurality of metadata.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the arrangement of an informationprocessing apparatus;

FIG. 2 is a view showing an example of summary information;

FIG. 3A and FIG. 3B are views showing an example of a method of creatingsummary information;

FIG. 4 is a timing chart showing a summary information creation methodin PTZ;

FIG. 5 is a view showing a case in which movie files and concatenatedmetadata files are hierarchically stored;

FIG. 6 is a view showing the correspondence between a movie andmetadata;

FIG. 7A and FIG. 7B are views showing examples of layer summaryinformation;

FIG. 8 is a flowchart illustrating storage processing;

FIG. 9 is a view showing a recording system; and

FIG. 10 is block diagram showing the arrangement of an informationprocessing apparatus.

DESCRIPTION OF THE EMBODIMENTS

The present invention will be described in detail below based on someembodiments with reference to the accompanying drawings. Note thatarrangements shown in the following embodiments are merely examples, andthe present invention is not limited to them.

FIG. 1 is a block diagram showing the arrangement of an informationprocessing apparatus 10. The information processing apparatus 10includes an image acquisition unit 101, a control informationacquisition unit 102, an encoding unit 103, an analysis unit 104, aparameter setting unit 105, a temporary storage unit 106, a summaryinformation creation unit 107, and a recording control unit 108.

The image acquisition unit 101 acquires an image from an externalimaging apparatus (not shown). Note that the information processingapparatus 10 may incorporate an imaging apparatus. The image acquisitionunit 101 acquires images from the imaging apparatus in, for example, atime sequence. The image acquisition unit 101 also assigns, to theplurality of acquired images, image IDs for identifying them,respectively. Alternatively, the image acquisition unit 101 may acquireimages assigned image IDs from the imaging apparatus. Note that theimages acquired by the image acquisition unit 101 are not limited toimages captured by the external imaging apparatus, and may be imagessaved in an external server or external memory.

The control information acquisition unit 102 acquires pan/tilt/zoominformation of a camera from the external imaging apparatus (not shown).The information acquired by the control information acquisition unit 102is not limited to the pan/tilt/zoom information of the camera, and maybe any information acquirable from the camera, such as white balance orexposure change information. In a mode in which summary information isnot divided for each piece of control information, the controlinformation acquisition unit 102 is not necessary.

The encoding unit 103 encodes each of continuous images acquired by theimage acquisition unit 101 in the H.264 format, and creates a gray imageby extracting only luminance values. Note that the encoding processingby the encoding unit 103 is not limited to the H.264 format, and may beany encoding processing which can encode continuous images in, forexample, a continuous JPEG or MPEG-2 format.

The analysis unit 104 uses the gray images created by the encoding unit103 to detect a moving object or stationary object by a backgroundsubtraction method. Furthermore, the analysis unit 104 assigns an ID(object ID) to an object identified based on the positional relationshipof the detected object between frames, and executes processing oftracking the object. Based on the characteristics of the shape andbehavior pattern of each object, the unit 104 assigns a human (male orfemale) attribute, a stationary object attribute, or another attribute.The unit 104 also detects the shape, position, size, movement locus, andthe like of each object.

Moreover, the analysis unit 104 detects an event (tripwire event) inwhich the movement locus of an object passes through a specific locationon a screen, and an event (abandoned event) in which an object stays atone location on the screen for a predetermined time or longer.

The analysis unit 104 creates metadata (first metadata) for each frameusing the obtained object and event, and the creation time of acorresponding image. Since an event may not be detected in all frames,metadata is associated with a frame in which an event has been detected.The data size of the frame is described at the beginning of themetadata.

The processing of the analysis unit 104 is not limited to theabove-described one, and may be any processing of creating metadata byanalyzing an image, such as moving object tracking using an inter-framesubtraction method or optical flow. In this embodiment, the analysisunit 104 acquires a gray image from the encoding unit 103. The presentinvention, however, is not limited to this, and the analysis unit 104may use an image directly acquired from the image acquisition unit 101.

In response to a user operation or the like, the parameter setting unit105 receives an upper limit value associated with metadata and encodedimages to be temporarily stored in the temporary storage unit 106. Morespecifically, the upper limit value indicates a file upper limit valueand a layer upper limit number for each layer. The file upper limitvalue represents a data amount, time, or the like to be temporarilystored, and is set for encoded images or metadata. The layer and thelayer upper limit number for each layer are required when the recordingcontrol unit 108 records information, and will be described in detaillater.

Furthermore, in response to a user operation or the like, the parametersetting unit 105 receives a summary information filter. The summaryinformation filter is used to specify contents to be described insummary information to be created by the summary information creationunit 107 (to be described later), and is at least one piece ofinformation described in the metadata.

The temporary storage unit 106 associates the image ID assigned by theimage acquisition unit 101 with the encoded image created by theencoding unit 103 and the metadata created by the analysis unit 104, andtemporarily stores them. If the amount of the temporarily stored encodedimages or metadata exceeds the aforementioned file upper limit value,the temporary storage unit 106 groups the stored encoded images andmetadata, and outputs them to the summary information creation unit 107.After that, the temporarily stored encoded images and the like arereset.

The summary information creation unit 107 acquires the encoded imagesand metadata from the temporary storage unit 106, and creates a moviefile and summary information (second metadata) based on the acquiredencoded images and metadata. In this example, the movie file has the MP4format, and the size, offset position, and the like of each encodedimage necessary for the MP4 file structure are created, and set in afile having the MP4 format. On the other hand, the summary informationincludes the range of the stored metadata, the presence/absence of anevent, the number of objects, and position information of each object,and is created according to the settings of the aforementioned summaryinformation filter.

FIG. 2 shows an example of the summary information described in the XMLformat. FIG. 2 shows a case in which the range of metadata (range), thepresence/absence or number of events (event), the attribute and numberof objects (human), and the position information of objects (area) areset in the summary information filter. The summary information filter isnot limited to these pieces of information, and may be set based oninformation such as the creation time of the summary information, theoccurrence time of each event, and the occurrence period of each event.

The range of the metadata indicates a range of the stored metadata onthe time axis using the image IDs assigned by the image acquisition unit101. That is, the range includes the image IDs of the first and lastimages of the group. In FIG. 2, it includes images from an image with animage ID “1000” to an image with an image ID “1300”.

The presence/absence or number of events indicates the presence/absenceor number of events for each event type (tripwire event (tripwire) orabandoned event (abandoned)) within the range of the stored metadata.FIG. 2 shows a case in which one tripwire event has been detected andone abandoned event has been detected.

The attribute of each object represents the object detected from aplurality of images output from the temporary storage unit 106. Thenumber of objects is obtained by counting, for each attribute, objectswithin the range of the stored metadata. FIG. 2 shows a case in whichfour males, three females, two cats, and four other objects have beendetected.

The position information of objects indicates a sum set of positions(coordinates) on the screen where the objects are detected within therange of the stored metadata. Referring to FIG. 2, in area 1 with xcoordinates of 400 to 580 and y coordinates of 50 to 130, a human andanother object have been detected and an abandoned event has beendetected. Furthermore, referring to FIG. 2, in area 2 with x coordinates0 to 170 and y coordinates of 230 to 320, a human and animal have beendetected and a tripwire event has been detected.

As an example different from that shown in FIG. 2, if only the range ofmetadata and the presence/absence of events are set as a summaryinformation filter, only the range of metadata and the presence/absenceof events are described in summary information.

FIG. 3A and FIG. 3B show an example of the gray image (FIG. 3A) and anexample of the created summary information (FIG. 3B). In the exampleshown in FIGS. 3A and 3B, as shown in FIG. 3A, the range of the metadatawill be referred to as one chunk section, and the one chunk sectionincludes a plurality of frames. The analysis unit 104 creates metadatafor each frame based on the detected objects and events. After framescorresponding to one chunk section elapse, the summary informationcreation unit 107 creates summary information based on the obtainedmetadata and encoded images.

This summary information is as shown in FIG. 3B. In this example, thesummary information includes pieces of information related to thedetected events. More specifically, the summary information indicatesthat a human and animal (Human, animal) and a tripwire event (tripwire)have been detected at one position (Area 1). The summary informationalso indicates that a human and another object (Human, object) and anabandoned event (abandoned) have been detected at another position (Area2).

That is, assume that the tripwire event has been detected in the nthimage within the chunk section and the abandoned event has been detectedin the (n+m)th image. The summary information of the chunk sectionincludes information indicating that each of the tripwire event andabandoned event has been detected in one of the images within the chunksection. The summary information also includes positions where thetripwire event and abandoned event have been detected, and theattributes of the detected objects (human, animal, and other).

If the notification of control information of the camera such aspan/tilt/zoom (PTZ) information of the camera is received from thecontrol information acquisition unit 102, pieces of summary informationare created. FIG. 4 shows a case in which a PTZ setting changenotification is received within the range of one piece of summaryinformation (one chunk section). Referring to FIG. 4, in Chunk n+1 ofthe stored metadata, the summary information creation unit 107 creates,as summary information s1, metadata from the beginning until the PTZsetting change notification is accepted. The unit 107 creates summaryinformation s2 during a PTZ change period, and creates summaryinformation s3 from when the PTZ change operation ends up to the end ofthe metadata. As described above, summary information is created foreach portion according to a change in control information.

Note that the control information received from the control informationacquisition unit 102 is not limited to PTZ information, and may be anycontrol information obtained from the camera, such as a white balancechange or exposure change. The control information of the camera isreflected on summary information.

In this embodiment, the movie file created by the summary informationcreation unit 107 has the MP4 format. The present invention, however, isnot limited to this, and any container which can form one movie fromencoded images such as AVI files can be used. Furthermore, although thesummary information created by the summary information creation unit 107has the XML format in this embodiment, the present invention is notlimited to this, and any format for managing the summary informationsuch as a binary format or a format having a unique structure may bepossible.

Contents described in the summary information are not limited to thosein this embodiment, and may be any contents obtained by summarizing thecontents of the metadata within the range of the stored metadata. Inthis embodiment, a change in control information of the camera isacquired from the control information acquisition unit 102. If, however,the control information exists in the header of an image acquired by theimage acquisition unit 101, this information may be used.

The recording control unit 108 hierarchically records, in an externalapparatus, the metadata stored in the temporary storage unit 106, thesummary information created by the summary information creation unit107, and movie files together.

FIG. 5 shows a case in which the recording control unit 108 stores, inthe external apparatus, MP4 files as movie files, and concatenatedmetadata files created from metadata. The MP4 file stores, for example,a movie of 5 sec, and the concatenated metadata file stores metadatadetected from each of a plurality of images included in the MP4 file inassociation with each of the plurality of respective images. FIG. 5shows a case in which there are four layers from Layer 0 to Layer 3.Recording is performed based on the layer upper limit number received bythe parameter setting unit 105. The layer upper limit number indicatesthe upper limit number of files or folders which can be stored in eachlayer.

Referring to FIG. 5, the layer upper limit number of Layer 3 is 15 MP4files or 15 concatenated metadata files, the layer upper limit number ofeach of Layer 2 and Layer 1 is set to 1000 folders. Note that the layerupper limit number is not limited to 1000. An MP4 file and concatenatedmetadata file have the same name but different extensions. One fileincluding an MP4 file and concatenated metadata file may be saved inLayer 3.

When saving an MP4 file and concatenated metadata file for the firsttime, the recording control unit 108 creates one folder in each of Layer1 and Layer 2. Folder names are 000 to 999 in the folder creation order.An MP4 file and concatenated metadata file are then saved in Layer 3 asthe lowest layer.

Layer summary information is created for each layer. If an MP4 file issaved in folder 000 in Layer 2, layer summary informationlayer3_(—)1meta is generated or updated. If there is no layer summaryinformation layer3_(—)1meta when an MP4 file is saved in folder 000 inLayer 2, layer summary information layer3_(—)1meta is generated. If thelayer summary information layer3_(—)1meta exists when an MP4 file issaved in folder 000 in Layer 2, the layer summary informationlayer3_(—)1meta is updated.

After that, if, when adding a file, the number of files in a folder witha smallest number (000 in FIG. 5) in Layer 2 is smaller than the layerupper limit number, the file is saved in the folder. On the other hand,if the number of files exceeds the layer upper limit number, a newfolder is created in Layer 2, and an MP4 file and concatenated metadatafile are saved in the new folder.

Note that if the number of a folder name in Layer 2 exceeds 999, a newfolder is created in Layer 1, and folders are created as describedabove, in which an MP4 file and concatenated metadata file are saved. Ifthe number of a folder name in Layer 1 exceeds the upper limit of 999,folder 000 in Layer 1 is deleted, and then files are saved in folder 000as described above. After that, in a similar manner, a deletionoperation is performed and then a saving operation is executed.

FIG. 6 shows an example of the structure of an MP4 file and concatenatedmetadata file to be recorded. In the MP4 file (movie file) shown in theupper portion, the header (Movie Header) of the MP4BOX structure isarranged at the beginning, and then encoded images Frame[0] to Frame[n]are continuously arranged. In the concatenated metadata file (metadatafile), pieces of summary information summary[0] and summary[1] createdby the summary information creation unit 107 are arranged at thebeginning, and then metadata Metadata[0] to Metadata[n] stored in thetemporary storage unit 106 are continuously arranged after the summaryinformation in association with the encoded images Frame[0] to Frame[n].The MP4 file and concatenated metadata file with the structure shown inFIG. 6 have the same name and different extensions. This associates theMP4 file with the concatenated metadata file. When the concatenatedmetadata file is saved, layer summary information is created andupdated.

Note that the pieces of summary information summary[0] and summary[1]and the concatenated metadata Metadata[0] to Metadata[n] need not alwaysbe recorded as one file, and may be recorded as different files.

Furthermore, the recording control unit 108 creates layer summaryinformation (third metadata) by summarizing pieces of summaryinformation for files or folders belonging to one layer, and updates itevery time contents are changed, thereby achieving layer management. Forexample, in Layer 3, layer summary information for 15 files is created(for example, layer3_(—)1.meta). In Layer 2, layer summary informationfor 999 folders in Layer 2 is created (for example, layer2_(—)1.meta).

FIG. 7A and FIG. 7B show examples of layer summary information describedin the XML format. In FIG. 7A, an example of the layer summaryinformation (the layer upper limit number is three files) in Layer 3 isshown. In FIG. 7B, an example of the layer summary information (thelayer upper limit number is three folders) in Layer 2 is shown. In eachpiece of layer summary information, the pan/tilt/zoom controlinformation and the presence/absence of events extracted from one ormore pieces of summary information stored in one folder are described inthe XML format.

The external apparatus in which the recording control unit 108 records amovie and concatenated metadata need only be a medium which can storedata, such as an SD card, hard disk, or NAS, and is not limited to aspecific device.

FIG. 8 is a flowchart illustrating the above-described storageprocessing. FIG. 8 shows part of a program executed by a computer forcontrolling the information processing apparatus 10. This computer readsout a program stored in a memory, and executes the processing shown inFIG. 8.

In step S1, it is determined whether to continue the storage processing.An image is acquired from the image acquisition unit 101 (step S2), andthe encoding unit 103 creates an encoded image (step S3). The analysisunit 104 performs analysis processing for the encoded image created instep S3 (step S4), and stores the encoded image and metadata in thetemporary storage unit 106 (step S5). If the number of encoded images ormetadata stored in the temporary storage unit 106 is smaller than thefile upper limit number, the process returns to the determinationprocessing in step S1 (step S6). On the other hand, if the number ofencoded images or metadata exceeds the file upper limit number, thesummary information creation unit 107 creates summary information (stepS7), and performs recording processing under the control of therecording control unit 108 (step S8). The temporary storage unit 106 isthen reset, and the process returns to the determination processing instep S1 (step S9).

FIG. 9 shows a recording system using the information processingapparatus according to this embodiment, and the operation of therecording system. Referring to FIG. 9, a camera 91 and a viewer 92 areconnected to each other by a wireless LAN, and the camera 91 and anetwork drive 93 are connected to each other by a wired LAN. Theinformation processing apparatus according to this embodiment is mountedon the camera 91. The information processing apparatus according to thisembodiment directly acquires an image from the camera 91, performsprocessing according to this embodiment, and outputs a result to thenetwork drive 93 to store it.

To play back only a movie in which an event has occurred, the viewer 92transmits a search message to the camera 91. Upon accepting the searchmessage, the camera 91 searches the network drive 93. For example, ifthe tripwire event is searched for, the presence/absence of the tripwireevent is checked sequentially from layer summary information in thehighest layer of the hierarchical structure of the network drive 93. Ifthe tripwire event exists, layer summary information in a lower layer ischecked. If the network drive 93 checks the presence/absence of thetripwire event from summary information attached to metadata, and findsthe event, it transmits a movie corresponding to a portion where theevent has occurred, and its metadata to the viewer 92 via the camera 91.The system arrangement is not limited to this, and the informationprocessing apparatus may be mounted on the network drive 93.

As described above, by hierarchically saving movie files andconcatenated metadata files according to the aforementioned arrangement,it is possible to improve the efficiency of a search process byhierarchically tracing the metadata. Note that in this embodiment, acase in which movie files are saved has been explained. The presentinvention is not limit to this, and is applicable to image filesincluding still image files.

FIG. 10 is a block diagram showing the arrangement of a recordingapparatus according to the second embodiment. This arrangement isbasically the same as that shown in FIG. 1 except that an imageacquisition unit 201 and metadata acquisition unit 202 are included. Theimage acquisition unit 201 acquires images captured by an externalimaging apparatus, and image IDs which have been assigned to the imagesby an external apparatus. The imaging apparatus and the apparatus forassigning an image ID may be a single apparatus or differentapparatuses.

The metadata acquisition unit 202 acquires metadata and image IDscorresponding to them from the external apparatus. The image IDs of theexternally acquired images and those of the metadata need not be in aone-to-one correspondence with each other, but an image and metadatacorresponding to each ID may have the same amount or time unit, as shownin FIG. 6.

When temporarily storing an image, image ID, and metadata in associationwith each other in a temporary storage unit 106, if there is no imagehaving an image ID corresponding to the metadata, an image having aclose image ID is associated with the metadata. Similarly, if there isno metadata with the image ID of metadata corresponding to the image, animage having the image ID of nearby metadata is associated with themetadata. Another arrangement is the same as that described in the firstembodiment, and recording control is executed for the externallyacquired images and metadata.

Although the embodiments have been explained in detail, the presentinvention can take, for example, a form of a system, an apparatus, amethod, a program, a recording medium (storage medium), or the like.More specifically, the present invention may be applied to a systemincluding a plurality of devices (for example, a host computer,interface device, imaging apparatus, and web application) or anapparatus including a single device.

Embodiments of the present invention can also be realized by a computerof a system or apparatus that reads out and executes computer executableinstructions recorded on a storage medium (e.g., non-transitorycomputer-readable storage medium) to perform the functions of one ormore of the above-described embodiments of the present invention, and bya method performed by the computer of the system or apparatus by, forexample, reading out and executing the computer executable instructionsfrom the storage medium to perform the functions of one or more of theabove-described embodiments. The computer may comprise one or more of acentral processing unit (CPU), micro processing unit (MPU), or othercircuitry, and may include a network of separate computers or separatecomputer processors. The computer executable instructions may beprovided to the computer, for example, from a network or the storagemedium. The storage medium may include, for example, one or more of ahard disk, a random-access memory (RAM), a read only memory (ROM), astorage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2012-203538, filed Sep. 14, 2012, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An image management apparatus comprising: ageneration unit configured to generate, from a plurality of metadatarespectively corresponding to a plurality of images, summary data of theplurality of metadata; and a storage unit configured to store thesummary data in association with the plurality of metadata.
 2. Theapparatus according to claim 1, wherein each of the plurality ofmetadata respectively corresponding to the plurality of images includesfirst metadata and second metadata, and the summary data of theplurality of metadata includes summary data of the first metadata andsummary data of the second metadata.
 3. The apparatus according to claim1, wherein each of the first metadata corresponding to a first image andthe second metadata corresponding to a second image indicates a presenceof an event detected in a corresponding one of the first image and thesecond image, and the summary data of the plurality of metadataincluding the first metadata and the second metadata indicates apresence of an event detected in one of a plurality of images includingthe first image and the second image.
 4. The apparatus according toclaim 1, wherein each of the first metadata corresponding to a firstimage and the second metadata corresponding to a second image indicatesa type of an event detected in a corresponding one of the first imageand the second image, and the summary data of the plurality of metadataincluding the first metadata and the second metadata indicates a type ofan event detected in one of a plurality of images including the firstimage and the second image.
 5. The apparatus according to claim 1,wherein each of the first metadata corresponding to a first image andthe second metadata corresponding to a second image indicates a positionof an object detected in a corresponding one of the first image and thesecond image, and the summary data of the plurality of metadataincluding the first metadata and the second metadata indicates aposition of an object detected in one of a plurality of images includingthe first image and the second image.
 6. The apparatus according toclaim 1, wherein each of the first metadata corresponding to a firstimage and the second metadata corresponding to a second image indicatesa presence of an abandoned event detected in a corresponding one of thefirst image and the second image, and the summary data of the pluralityof metadata including the first metadata and the second metadataindicates a presence of an abandoned event detected in one of aplurality of images including the first image and the second image. 7.The apparatus according to claim 1, wherein said generation unitgenerates first summary data from a plurality of first metadata, andgenerates second summary data from a plurality of second metadata, andsaid storage unit stores the first summary data in association with theplurality of first metadata, and stores the second summary data inassociation with the plurality of second metadata.
 8. The apparatusaccording to claim 1, further comprising a determination unit configuredto determine, based on the summary data, whether there exists an imagesatisfying a condition, among the plurality of images respectivelycorresponding to the plurality of metadata.
 9. The apparatus accordingto claim 1, wherein according to a change in state of an imaging unitfor shooting an image, said generation unit generates, from a pluralityof metadata respectively corresponding to a plurality of images shot bythe imaging unit before the state changes, the summary data.
 10. Theapparatus according to claim 1, wherein said generation unit generates,from a plurality of metadata respectively corresponding to a pluralityof images forming a video image, the summary.
 11. A management methodfor an image management apparatus, comprising: generating, from aplurality of metadata respectively corresponding to a plurality ofimages, summary data of the plurality of metadata; and storing thesummary data in association with the plurality of metadata.
 12. Themethod according to claim 11, wherein each of the plurality of metadatarespectively corresponding to the plurality of images includes firstmetadata and second metadata, and the summary data of the plurality ofmetadata includes summary data of the first metadata and summary data ofthe second metadata.
 13. The method according to claim 11, wherein eachof the first metadata corresponding to a first image and the secondmetadata corresponding to a second image indicates the presence of anevent detected in a corresponding one of the first image and the secondimage, and the summary data of the plurality of metadata including thefirst metadata and the second metadata indicates the presence of anevent detected in one of a plurality of images including the first imageand the second image.
 14. The method according to claim 11, furthercomprising determining, based on the summary data, whether there existsan image satisfying a condition, among the plurality of imagesrespectively corresponding to the plurality of metadata.
 15. The methodaccording to claim 11, further comprising generating, according to achange in state of an imaging unit for shooting an image, from aplurality of metadata respectively corresponding to a plurality ofimages shot by the imaging unit before the state changes, the summarydata.
 16. A storage medium storing a computer program executed by animage management apparatus, the computer program comprising generating,from a plurality of metadata respectively corresponding to a pluralityof images, summary data of the plurality of metadata; and storing thesummary data in association with the plurality of metadata.
 17. Themedium according to claim 16, wherein each of the plurality of metadatarespectively corresponding to the plurality of images includes firstmetadata and second metadata, and the summary data of the plurality ofmetadata includes summary data of the first metadata and summary data ofthe second metadata.
 18. The medium according to claim 16, wherein eachof the first metadata corresponding to a first image and the secondmetadata corresponding to a second image indicates the presence of anevent detected in a corresponding one of the first image and the secondimage, and the summary data of the plurality of metadata including thefirst metadata and the second metadata indicates the presence of anevent detected in one of a plurality of images including the first imageand the second image.
 19. The medium according to claim 16, wherein thecomputer program includes determining, based on the summary data,whether there exists an image satisfying a condition, among theplurality of images respectively corresponding to the plurality ofmetadata.
 20. The medium according to claim 16, wherein the computerprogram includes generating, according to a change in state of animaging unit for shooting an image, from a plurality of metadatarespectively corresponding to a plurality of images shot by the imagingunit before the state changes, summary data of the plurality ofmetadata.